Some times the most important aspect of identification is the location of the find. Looking at your profile I see that you have said that you live near the Queensland Museum in Brisbane Australia. Assuming that you have found these items near there I will make another suggestion. Brisbane Council has a Weed identification guide on its website which includes the tree Poinciana, Delonix regia. I believe what you have found is the seeds from this tree, they form in huge pods which then break open and the seeds are carried in waterways, often to the sea, for dispersal. If you do a google search for Delonix regia seed you will see what I maen.